|
|
|
|
| Author |
|
|
Registered User
|
Trying to stay positive
[Ok, I'm new to posting stuff, but have been investigating a no spark issue for a long time. I've been thru every check i can find on this site, Clarks, 944online, rennlist etc. I know you'll ask so, I have checked speed and ref sensors and have replaced them both, replaced dme relay and jumped it for giggles. Have replaced the coil, dme, cleaned every ground i can find, literally held the fuel pump in my hand while cranking, works fine. Fuel rail pressure is strong(wouldn't effect no spark anyway) but, checked, cleaned and heat shrank every connection i can get my hands on. voltage checks on Afm, and every other sensor and control unit i can find. Many other checks have been performed as per, pelican, clarks garage etc. Boils down to I have 12v to + side of coil, 5.88 to - side, and 3 to 3.4 going to dist. cap. The only change that occurs when cranking is; Voltage on + side drops 2 points during cranking. Car was running fine when I shut it off for work that morning and hasn't hit a lick since. About a week prior to that, it shut off all at once, but restarted without hesitation, never a spit, sputter, nothing. Been on this thing relentlessly for 6 months and I'm at a loss. Could use some ideas if anyone cares to help.
 I'll post pics soon, so not to be an outcast, lol.
Last edited by Troubled944; 11-16-2013 at 05:18 PM.. |
||
11-16-2013, 04:17 PM
|
|
|
Registered
|
Stay positive. If its none of the major things (which you've replaced), it must be something minor that you're overlooking..
__________________
2001 Porsche Boxster 1987 944S |
||
|
11-16-2013, 04:50 PM
|
|
|
Registered
|
For curiosity sake - are you checking for no spark at one of the spark plug wires, or at the coil to distributor wire?
__________________
'86 944 Turbo You have to be a masochist to love something so frustrating. |
||
|
11-16-2013, 05:05 PM
|
|
|
Registered User
|
I've checked for spark in both places. Did the spark test per Clarks Garage, and also checked from coil output wire with meter. Changed coil output wire also, just for the sake of it.
|
||
|
11-16-2013, 05:16 PM
|
|
|
Registered
Join Date: Oct 2002
Location: Boulder, CO
Posts: 1,196
|
What kind of car do you have? Alarm/disabler could be an issue, ignition amplifier module maybe. DME might be dead or associated wiring. The usual.
__________________
1987 928S4 1992 968 cabrio 2009 957 Cayenne GTS |
||
|
11-17-2013, 12:57 PM
|
|
|
Proprietoristicly Refined
Join Date: Jul 2001
Location: ~Carefree Highway~
Posts: 5,833
|
In your garage is an '83 automatic.
You replaced the DME. Do you mean you replaced the Motronic computer box with a similiar computer? What is the DME computer model number? Are they both the same? Original and spare? The automatic has an interlock connector under the shift selector knob. Has anyone rewired/cut/updated these wires? Did you try the Clarks method of grabbing the main computer 35 pin wire bundle and gently twisting-tugging while cranking. Just more ideas. J_AZ
__________________
1988 924S, 85,750K ..+ 1987 924S, 154K DD (+15K est. bad odo) |
||
|
11-17-2013, 02:17 PM
|
|
|
|
Registered User
|
Thanx John. The automatic is the problem child. I haven't tried the twisting thing, but i will, and my apologies for not describing which vehicle it is. It's an '83 944, and yes it was the Motronic that was switched from a running '83 model. I did do a conversion from the automatic flex plate, to the clutch, pressure plate and it works fantastic. i wasn't around the shifter, only the torque tube. I know it has trans lines running back but couldn't see any wiring and I did look. It ran great for a month or so after the conversion. I'll check. luckily the wiring is all original,'cept for some speaker wires. I wanna know more about the interlock connector.I by-passed the alarm early on.
|
||
|
11-18-2013, 03:12 PM
|
|
|
Registered User
|
two things i forgot to mention, the original coil and the first replacement coil would get extremely hot with just the key on( the coil housing) the wiring itself never did get hot. the third replacement stays cool. hopefully i fixed a bad ground. Secondly, the parking brake light stays on now with key on and didn't before. May be a separate issue, I don't know. Mechanically i can fix anything, electrically, not so much. I'm learning tho. And yes the Motronic #'s were the same.
|
||
|
11-22-2013, 03:57 PM
|
|
|
Registered
Join Date: Apr 2011
Location: north carolina
Posts: 114
|
Check injector harness for a broken wire under the insulation or lots of corrosion that was my problem on my 951....check to make sure injectors are firing with a noid light. It has to be some thing simple.
__________________
87 944 |
||
|
11-23-2013, 02:09 AM
|
|
|
Registered User
|
I'm getting 12v to both sides of injector 1. i'm thinking it's somewhere in the current flow with the green coil wire. With key on i get 5.88v at pin one, and 5.88v at coil neg. terminal (grn. wire). Would it make sense to check voltage where the grn wire connects to alarm jumper, just for tracking purposes? pardon me if these are stupid questions guys.
|
||
|
11-23-2013, 07:38 AM
|
|
1986 Porsche 951
